A typical example of a conventional accordion type bellows is shown in FIGS. 1 and 2.
FIG. 1 is an enlarged drawing of a part of the bellows shown in FIG. 2. The conventional bellows, as shown in FIG. 3, includes flexible members 3, each of which is formed so as to be flexible by bending a sheet member such as a cloth or a plastic sheet in a zig-zag fashion. Both ends of the cloth or sheet are fixed to opposing mounting plates 2 and reinforcement wires 4 are provided with the sheet member wound around them.
In the conventional bellows 1, when an external force is applied to the flexible member 3 from a direction as shown by the arrow A, the reinforcement wires 4 are bent backward and the flexible member 3 is irregularly bent. In order to overcome that drawback of the conventional bellows in FIG. 3, there has been proposed a bellows having plastic plates 5 attached to planar portions of the flexible member 3, as shown in FIG. 4. The plastic plates 5, however, cause the thickness of the bellows to be greatly increased when it is collapsed.